One of the major criticisms of optimal foraging theory (OFT) is that it is not testable. In discussions of this criticism opposing parties have confused methodological concepts and used meaningless biological concepts. In this paper we discuss such misunderstandings and show that OFr has an empirically testable, and even well-confirmed, general core theory. One of our main conclusions is that specific model testing should not be aimed at proving optimality, but rather at identifying the context in which certain types of (...) behaviour are optimal. To do this, it is necessary to be aware of the assumptions made in testing a model. The assumptions that are explicitly stated in the literature up to now do not completely cover the actual assumptions made in testing OFT models in practice. We present a more comprehensive set of assumptions. Although all the assumptions play a role in testing models, they are not of equal status. Crucial assumptions concern constraints and the relation between fitness and currency. Therefore, it is essential to make such assumptions testable in practice. We show that a more explicit relationship between OFT modelling and evolutionary theory can help with this. Specifically, phylogeny reconstruction and population dynamic modelling can and should be used to formulate assumptions concerning constraints and currencies. (shrink)

Methodological analysis shows that the concepts of fitness and adaptation are more complex than the literature suggests. Various arguments against ‘adaptationism’ are inadequate since they are couched in terms of unduly simplistic notions.

The impact of philosophy of science on biology is slight. Evolutionary biology, however, is nowadays an exception. The status of the neo-Darwinian theory of evolution is seriously challenged from a methodological perspective. However, the methodology used in the relevant discussions is plainly defective. A correct application of methodology to evolutionary theory leads to the following conclusions. The theory of natural selection is unfalsifiable in a strict sense of the term. This, however, does not militate against the theory, because no scientific (...) theory whatever is testable in this way. Under a more liberal testability criterion, the theory is surely testable. None the less, certain research programs may tend to make the theory untestable in practice. It has often been argued that the tautologous character of the principle of natural selection, allegedly the focus of evolutionary theory, makes the theory untestable through circular reasoning. Actually, the principle is only a tautology if ‘fitness’ is wrongly defined in terms of actual survival. But even then circular reasoning need not ensue. Evolutionary principles do not permit, without additional information, the derivation of statements about evolutionary events concerning particular species or populations. If this were a reason to criticize the theory , any other scientific theory would be inadequate by the same token. (shrink)